Posted on by Tammy Plotner

Trojan Asteroid Found Orbiting Uranus

One of three discovery images of 2011 QF99 taken from CFHT on 2011 October 24 (2011 QF99 is inside the green circle). This is the first of three images of the same patch of sky, taken one hour apart, that were then compared to find moving light-sources.

What’s new in the outer reaches of our solar system? Try the discovery of a Trojan asteroid orbiting Uranus. While a plethora of puns exist for this simple fact, the reality check is that this means there are far more of these objects out there than astronomers expected. The new Trojan even has a name – 2011 QF99!

A Trojan asteroid is a transient space rock which is temporarily captured by the gravity of a giant planet. It shares the planet’s orbital path, locked into a specific position known as a Lagrange point. What makes 2011 QF99 unusual is its presence in the outer solar system. Researchers found the scenario a bit unlikely. Why? The answer is simply because of planet size. According to theory, the strong gravitational pull of the larger neighboring planets should have destabilized any captured asteroid’s orbit and shot Uranian Trojans out of the neighborhood long ago.

So just how did this 60 kilometer-wide conglomeration of ice and rock end up circling Uranus? Astronomers turned towards computer modeling for the answer. The research team, including UBC astronomers Brett Gladman, Sarah Greenstreet and colleagues at the National Research Council of Canada and Observatoire de Besancon in France, did a simulation of the solar system and its co-orbital objects – including Trojan asteroids. A short-term animation showing the motion of 2011 QF99, as seen from above the north pole of the solar system can be found here.

“Surprisingly, our model predicts that at any given time three percent of scattered objects between Jupiter and Neptune should be co-orbitals of Uranus or Neptune,” says Mike Alexandersen, lead author of the study to be published tomorrow in the journal Science.

Until now, no one had made any estimates on the percentage of possible outer solar system Trojans. Unexpectedly, the amount ended up being far greater than earlier estimates. Just over the last 10 years, several temporary Trojans and co-orbitals have been cataloged and 2011 QF99 is one of them. It made its home around Uranus within the last few hundred thousand years and will eventually – in about a million years – escape Uranus’ gravity.

“This tells us something about the current evolution of the solar system,” says Alexandersen. “By studying the process by which Trojans become temporarily captured, one can better understand how objects migrate into the planetary region of the solar system.”

Original Story Source: UBC News Release.

Posted on by Elizabeth Howell

Uranus Is Being Chased By Asteroids!

A Sharper View Of Uranus
Uranus viewed in the infrared spectrum, revealing internal heating and its ring system. Image Credit: Lawrence Sromovsky, (Univ. Wisconsin-Madison), Keck Observatory

As Uranus speeds in its orbit in the solar system, there are three large space rocks that are in lockstep with the gas giant, according to new simulations. Two of them are wobbling in unstable “horseshoe” orbits near Uranus, while the third is in a more reliable Trojan orbit that is always 60 degrees in front of the planet.

The largest of this small group is the asteroid Crantor, which is 44 miles (70 kilometers) wide. Its horseshoe orbit, and that of companion 2010 EU65, means the space rocks seesaw between being close to Uranus and further away. They should stay in that configuration for a few million years.

The last of the group is 2011 QF99, in a Trojan orbit near one of Uranus’ Lagrangian points — sort of like a celestial parking spot where an object can hang out without undue influence from the balanced gravitational forces.

An artists impression of an asteroid belt(credit: NASA)
An artists impression of an asteroid belt(credit: NASA)

The results illustrate the importance of space rocks that are outside of the main asteroid belt between Mars and Jupiter.

There are several kinds of these asteroids (classified by their orbits) that follow around planets in the solar system. Earth itself, for example, has at least one Trojan asteroid.

“Crantor currently moves inside Uranus’ co-orbital region on a complex horseshoe orbit. The motion of this object
is primarily driven by the influence of the Sun and Uranus, although Saturn plays a significant role in destabilizing its orbit,” the authors wrote in their new study.

“Although this object follows a temporary horseshoe orbit, more stable trajectories are possible and we present 2010 EU65 as a long-term horseshoe librator candidate in urgent need of follow-up observations.”

The results are described in Crantor, a short-lived horseshoe companion to Uranus  (Astronomy & Astrophysics, March 3, 2013.)

Source: Servicio de informacíon y noticias cientifícas

Posted on by Jason Major

27 Years Ago: Voyager 2’s Visit to Uranus

Image of Uranus’ crescent taken by a departing Voyager 2 on January 25, 1986 (NASA/JPL)

27 years ago today, January 24, 1986, NASA’s Voyager 2 spacecraft sped past Uranus, becoming simultaneously the first and last spacecraft to visit the blue-tinged gas giant, third largest planet in the Solar System.

The image above shows the crescent-lit Uranus as seen by Voyager 2 from a distance of about 965,000 km (600,000 miles.) At the time the spacecraft had already passed Uranus and was looking back at the planet on its way outwards toward Neptune.

Although composed primarily of hydrogen and helium, trace amounts of methane in Uranus’ uppermost atmosphere absorb most of the red wavelengths of light, making the planet appear a pale blue color.

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Image of the 1,500-km-wide Oberon acquired by Voyager 2 on Jan. 24, 1986 (NASA/JPL)

The second of NASA’s twin space explorers (although it launched first) Voyager 2 came within 81,800 kilometers (50,600 miles) of Uranus on January 24, 1986, gathering images of the sideways planet, its rings and several of its moons. Voyager 2 also discovered the presence of a magnetic field around Uranus, as well as 10 new small moons.

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Three moons discovered by Voyager 2 in 1986 (NASA/JPL)

Data gathered by Voyager 2 revealed that Uranus’ rate of rotation is 17 hours, 14 minutes.

At the time of this writing, Voyager 2 is 15,184,370,900 km from Earth and steadily moving toward the edge of the Solar System at a speed of about 3.3 AU per year. At that distance, signals from Voyager take just over 14 hours and 4 minutes to reach us.

See images from Voyager 2’s visit of Uranus here, and check out a video of the August 20, 1977 launch below along with more images from the historic Voyager mission’s “Grand Tour” of the outer Solar System.

Posted on by Nancy Atkinson

Uranus has Bizarre Weather

New infrared images of Uranus show details not seen before. Credit: NASA/ESA/L. A. Sromovsky/P. M. Fry/H. B. Hammel/I. de Pater/K. A. Rages

Here’s the scene: a thick, tempestuous atmosphere with winds blowing at a clip of 900 km/h (560 mph); massive storms that would engulf continents here on Earth, and temperatures in the -220 C (-360 degree F) range. Sounds like a cold Hell, but this is the picture emerging of the planet Uranus, revealed in new high-resolution infrared images from the Keck Observatory in Hawaii, exposing in incredible detail the bizarre weather of a planet that was once thought to be rather placid.

“My first reaction to these images was ‘wow’ and then my second reaction was ‘WOW,'” said Heidi Hammel, a co-investigator on the new observations. “These images reveal an astonishing amount of complexity in Uranus’ atmosphere. We knew the planet was active, but until now much of the activity was masked by noise in our data.”

Voyager 2’s view of Uranus. Credit: NASA

With its beautiful blue atmosphere, Uranus can seem rather tranquil at first glance. Even the flyby of Voyager 2 in 1986 revealed a rather “bland” blue ball. But coming into focus now with the new are large weather systems, and even though they are probably much less violent than storms on Earth, the weather on Uranus is just…bizarre.

“Some of these weather systems,” said Larry Sromovsky, from the University of Wisconsin-Madison who led the new study using the Keck II telescope, “stay at fixed latitudes and undergo large variations in activity. Others are seen to drift toward the planet’s equator while undergoing great changes in size and shape. Better measures of the wind fields that surround these massive weather systems are the key to unraveling their mysteries.”

Sromovsky, Hammel and their colleagues are using new infrared techniques to deliver some of the “most richly detailed views of Uranus yet obtained by any instrument on any observatory. No other telescope could come close to producing this result,” Sromovsky said.

What they are seeing are previously undetected, small but widely distributed weather feature, and they hope the movements of these features can help make sense of the planet’s odd pattern of winds.

They observed a scalloped band of clouds just south of Uranus’ equator and a swarm of small convective features in the north polar regions of the planet. Features like this don’t seem to be in the southern polar regions, but are similar to the types of “popcorn” –type clouds seen on Saturn. Uranus’ north pole is not visible from Earth night now, but when it does come into view, the researchers wouldn’t be surprised to see a polar vortex feature similar to what has been seen at Saturn’s south pole.

The driver of these features must be solar energy because there is no other detectable internal energy source.

“But the Sun is 900 times weaker there than on Earth because it is 30 times further from the Sun, so you don’t have the same intensity of solar energy driving the system,” said Sromovsky. “Thus the atmosphere of Uranus must operate as a very efficient machine with very little dissipation. Yet the weather variations we see seem to defy that requirement.”

One possible explanation, is that methane is pushed north by an atmospheric conveyor belt toward the pole where it wells up to form the convective features visible in the new images. The phenomena may be seasonal, the team said, but they are still working on trying to put together a clear seasonal trend in the winds of Uranus.

“Uranus is changing,” he said, “and there is certainly something different going on in the two polar regions.”

The images were released at the American Astronomical Society’s Division for Planetary Sciences meeting taking place this week.

Source: University of Wisconsin-Madison

Posted on by Nancy Atkinson

The Moon from Earth As You’ve Never Seen it Before

The Morteus region on the Moon, taken from the suburbs of Paris, France. Credit: Thierry Legault. Used by permission.

Think this is an orbital view of the Moon? Guess again. Astrophotographer Thierry Legault took this image from his backyard in the suburbs of Paris, France! He’s taken a series of images of the Moon the past few nights that will blow your mind when you consider they were taken from Earth, within the confines of the metropolis of Paris (largest city in France, 5th largest in the EU, 20th largest in the world). Thierry used a Celestron C14 EdgeHD (356mm) and Skynyx2.2 camera. You definitely want to click on these images for the larger versions on Thierry’s website, and he suggests using a full-HD screen in subdued surroundings.

Additionally, Thierry also recently took images of Mercury and Uranus that include incredible detail.

Plato, Mons Pico and Montes Teneriffe as seen on Sept 8th, 2010, from the suburbs of Paris, France. Credit: Thierry Legault. Used by permission.

The clarity and detail are just tremendous. See all of Thierry’s recent lunar images at this link. He has a collection of twelve different images of various regions on the Moon and all are stunning.

Below are his images of Mercury and Uranus. In the image of Mercury, surface details are visible, and the cloud belts are even visible on the images of Uranus:

Incredibly detailed view of Mercury on August 23, 2012, as seen from Blancourt, France. Credit: Thierry Legault. Used by permission.

Uranus, as seen on September 9, 2012 from Blancourt, France. Credit: Thierry Legault. Used by permission.

Thanks, as always, to Thierry Legault for sharing his images and allowing us to post them. Check out his website: http://legault.perso.sfr.fr/ for more wonderful images and information about how he does his amazing astrophotography.

Posted on by Jason Major

Hubble Reveals Curious Auroras on Uranus

Bright spots of Uranus' short-lived auroras have been imaged with the Hubble Space Telescope.

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Astronomers have finally succeeded in capturing the first Earth-based images of the curious and fleeting auroras of Uranus using the Hubble Space Telescope, careful planning… and no small amount of luck.

Unlike Earthly auroras, whose long-lived curtains of glowing green, red and purple have been the subject of countless stunning photos over the past months, Uranus’ auroras are relatively dim and short-lived, lasting only several minutes at most. They were first witnessed on Uranus by Voyager 2 in 1986, but never by any Earth-based telescopes until November of 2011. Using Hubble, an international team of astronomers led by Laurent Lamy from the Observatoire de Paris in Meudon, France spotted two instances of auroras on the distant planet… once on November 16 and again on the 29th.

Two instances of Uranian aurora imaged in Nov. 2011. (L. Lamy)

Auroras are known to be created by a planet’s magnetosphere, which on Earth is aligned closely with the rotational axis — which is why auroras are seen nearest the polar latitudes. But Uranus’ magnetic field is quite offset from its rotational axis, which in turn is tipped nearly 98 degrees relative to its orbital path. In other words, Uranus travels around the Sun rolling on its side! And with a 60-degree difference between its magnetic and rotational axis, nothing on Uranus seems to point quite where it should. This — along with its 2.5-billion-mile (4 billion km) distance — makes for a “very poorly known” magnetic field.

“This planet was only investigated in detail once, during the Voyager flyby, dating from 1986. Since then, we’ve had no opportunities to get new observations of this very unusual magnetosphere,” said Laurent Lamy, lead author of the team’s paper Earth-based detection of Uranus’ aurorae.

Rather than rings of bright emissions, as witnessed on Earth as well as Saturn and Jupiter, the Uranian auroras appeared as bright spots of activity on the planet’s daytime side — most likely a result of Uranus’ peculiar orientation, as well as its seasonal alignment.

It’s not yet known what may be happening on Uranus’ night side, which is out of view of Hubble.

When Voyager 2 passed by Uranus in 1986 the planet was tipped such that its rotational axis was aimed toward the Sun. This meant that its magnetic axis —  offset by 60 degrees — was angled enough to encounter the solar wind in much the same way that Earth’s does. This created nightside auroras similar to Earth’s that Voyager saw.

By 2011, however, Uranus — which has an 84-year-long orbit — was near equinox and as a result its magnetic axis was nearly perpendicular with its orbital plane, aiming each end directly into the solar wind once a day. This makes for very different kinds of auroras than what was seen by Voyager; in fact, there’s really nothing else like it that astronomers know of.

“This configuration is unique in the solar system,” said Lamy.

Further investigations of Uranus’ auroras and magnetic field can offer insight into the dynamics of Earth’s own magnetosphere and how it interacts with the solar wind, which in turn affects our increasingly technological society.

The team’s paper will be published Saturday in Geophysical Research Letters, a journal of the American Geophysical Union.

Read the release from the AGU here.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast – March 12-18, 2012

Venus & Jupiter above Backyard Observatory - Credit: John Chumack

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Greetings, fellow SkyWatchers! What an awesome display of planets! Please take the time to walk outdoors just after skydark – regardless of where you live – and enjoy the bright display of Venus and Jupiter! However, this isn’t the only planetary action going on this week… Mars and M96 pair up, as well as Uranus and the Moon. There’s even a Southern Hemisphere meteor shower to enjoy! Pretty exciting, huh? Join the party by getting out your binoculars or telescopes and meet me for more in the backyard…

Monday, March 12 – No. That’s not the “headlights” of a UFO on the western horizon tonight… It’s a very cool pairing of Venus and Jupiter! It’s not often you see the two visually brightest planets making a close visual pass at each other and tonight you’ll spot the inner planet to the south and the outer planet to the north. This would make a great photo opportunity! Why not consider adding something interesting to your picture like a scenic building, tree, or even a person? Watch in the days ahead as Jupiter appears to stay in the same spot at the same time, yet Venus will climb higher.

Tonight let’s return again to NGC 2362 and start at the cluster’s north-northeast corner to have a look at a single, unusual star – UW Canis Majoris. At magnitude 4.9, this super-giant spectroscopic binary is one of the most massive and luminous in our galaxy. Its two stars are separated by only 27 million kilometers (17 million miles) and revolve around each other at a frenzied pace – in less than four and a half days. This speed means the stars themselves are flattened and would appear to be almost egg-shaped. The primary itself is shedding material that’s being collected by the secondary star.

Now drop southwest of NGC 2362 for another open cluster – NGC 2354 (Right Ascension: 7 : 14.3 – Declination: -25 : 44). While at best this will appear as a small, hazy patch to binoculars, NGC 2354 is actually a rich galactic cluster containing around 60 metal-poor members. As aperture and magnification increase, the cluster shows two delightful circle-like structures of stars, similar to a figure 8. Be sure to make a note… You’ve captured another Herschel 400 object!

Tuesday, March 13 – On this day in 1781, Uranus was discovered by William Herschel. Also on this day, in 1855, Percival Lowell was born in Boston. Educated at Harvard, Lowell went on to found the observatory which bears his name in Flagstaff, Arizona, and spent a lifetime studying Mars. During the early morning hours, you can honor Lowell by seeing Mars yourself – it’s best viewed when as high a possible on the ecliptic. While there won’t be a great many details, think of how many strides have been made since Lowell’s time and how advanced our knowledge of Mars has become!

Tonight let’s hop about four fingerwidths east-northeast of Sirius. Look for 5th magnitude SAO 152641 to guide you to a faint patch of stars in binoculars and a superb cluster in a telescope – NGC 2360 (Right Ascension: 7 : 17.8 – Declination: -15 : 37). Comprised of around eighty 10th magnitude and fainter stars, this particular cluster will look like a handful of diamond dust scattered on the sky. Discovered by Caroline Herschel in 1783, this intermediate-aged galactic cluster is home to red giants and heavy in metal abundance. Mark your notes, because not only is this a Herschel object, but is known as Caldwell 58 as well!

Wednesday, March 14 – Today is the birthday of Albert Einstein. Born in 1879, Einstein was one of the finest minds of our times. He developed the theory of gravity in terms of spacetime curvature – dependent on the energy density. Winner of the 1921 Physics Nobel prize, Einstein’s work on the photoelectric effect is the basis of modern light detectors.

Tonight let’s hop about a fistwidth north of bright Eta Canis Majoris and have a look at a “double cluster” – NGC 2383 (Right Ascension: 7 : 24.8 – Declination: -20 : 56) and NGC 2384 (Right Ascension: 7 : 25.1 – Declination: -21 : 02). Just showing in binoculars as a faint patch, this pair will begin resolution with larger scopes. Studied photometrically, it would appear these fairly young clusters have contaminated each other by sharing stars – which has also occurred in some clusters located in the Magellanic Clouds. Enjoy this unusual collection of stars…

Thursday, March 15 – Today celebrates the birth of Nicolas Lacaille. Born in 1713, Lacaille’s measurements confirmed the Earth’s equatorial bulge. He also named fourteen southern constellations. To honor Lacaille tonight, let’s begin some explorations in a constellation he named – Puppis!

For SkyWatchers living in high northern latitudes, you’ll never see all of this constellation, but there will be some things for you to explore, as well as a great deal for our friends in the southern hemisphere. The first is a Herschel object that lies directly on the galactic equator around five degrees north-northwest of Xi.

NGC 2421 (Right Ascension: 7 :36.3 – Declination: -20 : 37) is a magnitude 8.3 open cluster that will look like an exquisitely tiny “Brocchi’s Cluster” in binoculars and begin good resolution of its 50 or so members to an intermediate telescope, in an arrowhead-shaped pattern. It’s bright, it’s fairly easy to find, and it’s a great open cluster to add to your challenge study lists!

If you’re looking for a curiosity, then look no further than Leo and Mars. Tonight the happy red planet is situated just to the east of Messier 96 (Right Ascension: 10 : 46.8 – Declination: +11 : 49)! Enjoy celestial mechanics over the next few nights as Mars gently changes its position in relation with this distant galaxy… and gets much closer!

Friday, March 16 – On this day in 1926, Robert Goddard launched the first liquid-fuel rocket. But he was first noticed in 1907 when a cloud of smoke issued from a powder rocket fired in the basement of the physics building in Worcester Polytechnic Institute. Needless to say, the school took an interest in the work of this shy student. Thankfully they did not expel him, and thus began his lifetime of work in rocket science. Goddard was also the first to realize the full implications of rocketry for missiles and space flight, and his lifetime of work was dedicated to bringing this vision to realization. While most of what he did went unrecognized for many years, tonight we celebrate the name of Robert H. Goddard. This first flight may have gone only 12 meters, but forty years later on the date of his birth, Gemini 8 was launched, carrying Neil Armstrong and David Scott into orbit!

Let’s begin our observing evening with Mars. While you may have been keeping track of its position, did you know that it’s less than a degree away from a Messier object tonight? That’s right! You’ll find the dusty red planet just to the north of M96 (Right Ascension: 10 : 46.8 – Declination: +11 : 49).

Tonight we’ll pick up a challenge cluster and a planetary nebula on the Herschel list by returning to NGC 2421 and hopping about a fingerwidth northeast for NGC 2432 (Right Ascension: 7 : 40.9 – Declination: -19 : 05). This small, loose open cluster is rather dim and contains around 20 or so faint members shaped like the letter B. About another degree northeast is NGC 2440 – an elongated, small 11th magnitude planetary nebula. Look for its central star to cause a brightening and up the magnifying power to reveal it.

While out, be on watch for the Corona-Australids meteor shower. While the fall rate is low – 5 to 7 per hour – our friends in the southern hemisphere might stand a chance with this one!

Saturday, March 17 – On this day in 1958, the first solar-powered spacecraft was launched. Named Vanguard 1, it was an engineering test satellite. From its orbital position, the data taken from its transmission helped to redefine the true shape of the Earth.

Tonight let’s return to Xi Puppis and head less than a fingerwidth east-northeast for Herschel study NGC 2482 (Right Ascension: 7 : 54.9 – Declination: -24 : 18). At magnitude 7, this small fuzzy spot in binoculars will resolve into around two dozen stars to the telescope. Look for the diagonal chain of stars along its edge.

Now let’s have a look at an open cluster easily located in northeastern Orion. This 5.9 magnitude scattered group of stars may have been first observed by Giovanni Batista Hodierna in the mid-17th century. While bright enough to have been a Messier object, William Herschel added it to his log of discoveries on October 15, 1784, as H VIII.24. Of the 30 known stars associated with this 3,600 light-year distant group, the brightest is 50 million years old. A half-dozen of the cluster’s very brightest members can be seen in small scopes at mid-range powers. Look for NGC 2169 (Right Ascension: 6 : 08.4 – Declination: +13 : 57) slightly less than a fist width north-northeast of Betelguese and slightly south of Xi and Nu Orionis.

Sunday, March 18 – Although you can’t see it with just your eyes, Uranus is less than a degree from the Moon this morning. For some areas this could be an occultation, so be sure to check IOTA information!

Today in 1965, the first ever spacewalk was performed by Alexei Leonov onboard the Soviet Voskhod spacecraft. The “walk” only lasted around 20 minutes and Alexei had problems in re-entering the spacecraft because his space suit had enlarged slightly. Imagine his fear as he had to let air leak out of his space suit in order to squeeze back inside. When they landed off target in the heavily forested Ural Mountains, the crew of two had to spend the night in the woods surrounded by wolves. It took over twenty-four hours before they were located and workers had to chop their way through the forest and recover them on skis. Brave men!

Tonight let’s honor them by studying a small area which contains not only three Herschel objects – but two Messiers as well – M46 and M47. You’ll find them less than a handspan east of Sirius and about a fistwidth north of Xi Puppis.

The brighter of the two clusters is M47 (Right Ascension: 7 : 36.6 – Declination: -14 : 30) and at 1600 light-years away, it’s a glorious object for binoculars. It is filled with mixed magnitude stars that resolve fully to aperture with the double Struve 1211 near its center. While M47 is in itself a Herschel object, look just slightly north (about a field of view) to pick up another cluster which borders it. At magnitude 6.7, NGC 2423 isn’t as grand, but it contains more than two dozen fairly compressed faint stars with a lovely golden binary at its center.

Now return to M47 and hop east to locate M46 (Right Ascension: 7 : 41.8 – Declination: -14 : 49). While this star cluster will appear to be fainter and more compressed in binoculars, you’ll notice one star seems brighter than the rest. Using a telescope, you’ll soon discover the reason. 300 million year old M47 contains a Herschel planetary nebula known as NGC 2438 in its northern portion. The cluster contains around 150 resolvable stars and may involve as many as 500. The bright planetary nebula was first noted by Sir William Herschel and then again by John. While it would appear to be a member of the cluster, the planetary nebula is just a little closer to us than the cluster. Be sure to mark your notes… There’s a lot there in just a little area!

Until next week? May all of your journeys be at light speed!

Many thanks to John Chumack for the inspiring image!

Posted on by VirtualAstro

Night Sky Guide: February 2012

Special thanks to Ninian Boyle astronomyknowhow.com for information in parts of this guide

This month, the Solar System gives us a lot to observe and we’ll even start to see the ‘spring’ constellations appear later in the evenings. But February still has the grand constellations of winter, with mighty Orion as a centrepiece to long winter nights.

The Sun has finally started to perform as it should as it approaches “Solar Maximum.” This means we get a chance to see the northern lights (Aurora), especially if you live in such places as Scotland, Canada, Scandinavia, or Alaska or the southern light (Aurora Australis) if you live in the southern latitudes of South America, New Zealand and Australia. Over the past few weeks we have seen some fine aurora displays and will we hope to seesome in February!

We have a bit of a treat in store with a comet being this month’s favourite object with binoculars as well, so please read on to find out more about February’s night sky wonders.

You will only need your eyes to see most of the things in this simple guide, but some objects are best seen through binoculars or a small telescope.

So what sights are there in the February night sky and when and where can we see them?

Aurora

Looking north from the science operations center at Poker Fla,Alaska. Credit: Jason Ahrns.

The Aurora or Northern Lights (Aurora Borealis) have been seen from parts of Northern Europe and North America these last few weeks. This is because the Sun has been sending out huge flares of material, some of which have travelled towards us slamming into our magnetic field. The energetic particles then follow the Earth’s magnetic field lines towards the poles and meet the atoms of our atmosphere causing them to fluoresce, similar to what happens in a neon tube or strip light.

The colours of the aurora depend on the type of atom the charged particles strike. Oxygen atoms for example usually glow with a green colour, with some reds, pinks and blues. So the more active the Sun gets, the more likely we are to see the Northern (or Southern) Lights.

All you need to see aurora is your eyes, with no other equipment is needed. Many people image the aurora with exposures of just a few seconds and get fantastic results. Unfortunately auroras are “space weather” and are almost as difficult to predict as normal terrestrial weather, but thankfully we can be given the heads up of potential geomagnetic storms by satellites monitoring the Sun such as “STEREO” (Solar TErrestrial RElations Observatory).

Spaceweather.com is a great resource for aurora and other space weather phenomenon and the site has real-time information on current aurora conditions and other phenomenon.

Planets

Mercury is too close to the Sun to be seen at the beginning of the month, but will be visible very low in the south west from the 17th onwards. At the end of February Mercury will be quite bright at around mag -0.8 and will be quite a challenge. It can be seen for about 30 minutes after sunset.

Venus will improve throughout the month in the south west and will pass within half a degree of Uranus on the 9th of February. You can see this through binoculars or a small telescope. On the 25th Venus and the slender crescent Moon can be seen together a fabulous sight. At the end of month Venus closes in on Jupiter for a spectacular encounter in March.

Venus

Mars can easily be spotted with the naked eye as a salmon pink coloured “star” and starts off the month in the constellation of Virgo and moves into Leo on the 4th. Mars is at opposition on March 3rd but is also at its furthest from the Sun on the 15th February making this opposition a poor one with respect to observing due to its small apparent size. The planet will still be visually stunning throughout the month.

Mars

Jupiter starts off the month high in the south as darkness falls and is still an incredibly bright star-like object. Through good binoculars or a small telescope you can see its four Galilean moons – a fantastic sight. On the 8th at around 19:50 UT, Europa will transit Jupiter and through a telescope you will see the tiny moons shadow move across its surface. Throughout February, Jupiter moves further west for its close encounter with Venus in March.

Jupiter

Saturn rises around midnight in the constellation of Virgo and appears to be a bright yellowish star. Through a small telescope you will see the moon Titan and Saturn’s rings as well.

Saturn

Uranus is now a binocular or telescope object in the constellation of Pisces. On the 9th Uranus and the planet Venus will be within half a degree of each other.

Uranus

Neptune is not visible this month.

Comets

Comet Garradd Credit: astronomy.com

Comet Garradd is still on show early in the month — if you have binoculars — and as the month progresses the viewing should improve. You can find the comet in the constellation of Hercules not far from the globular cluster M92. It is about a half a degree away or around the same width as the full Moon. The comet is around magnitude 7 or a little fainter than the more famous globular cluster M13 also to be found in Hercules, so you will definitely need binoculars to see it. The comet is heading north over the course of the month which should mean that it will become a little easier to see. At the beginning of the month you will have to get up early to see it, the best time being around 5:30 to 6:30 GMT. By the end of the month though, it should be visible all night long.

Moon phases

  • Full Moon – 7th February
  • Last Quarter – 14th February
  • New Moon – 21st February

Constellations

In February, Orion still dominates the sky but has many interesting constellations surrounding it.

Above and to the left of Orion you will find the constellation of Gemini, dominated by the stars Castor and Pollux, representing the heads of the twins with their bodies moving down in parallel lines of stars with each other.

Legend has it that Castor and Pollux were twins conceived on the same night by the princess Leda. On the night she married the king of Sparta, wicked Zeus (disguised as a swan) invaded the bridal suite, fathering Pollux who was immortal and twin of Castor who was fathered by the king so was mortal.

Castor and Pollux were devoted to each other and Zeus decided to grant Castor immortality and placed Castor with his brother Pollux in the stars.

Gemini has a few deep sky objects such as the famous Eskimo nebula and some are a challenge to see. Get yourself a good map, Planisphere or star atlas and see what other objects you can track down.

Credit: Adrian West

 

Posted on by VirtualAstro

Night Sky Guide: January 2012

January Sky Northern Hemisphere Credit: Adrian West

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January brings us striking views of the night skies! You’ll be able to see well known constellations during the long hours of darkness in the Northern hemisphere, with crisp cold skies. This is an ideal time to get out and look at the wonders of the night sky as there is so much to see for the beginner and seasoned astronomer alike.

You will only need your eyes to see most of the things in this simple guide, but some objects are best seen through binoculars or a small telescope.

So what sights are there in the January night sky and when and where can we see them?

Meteor Showers

Quadrantid Meteor Credit: nasa.gov

As soon as the month starts we receive a welcome treat in the form of the Quadrantid meteor shower on the evening of the 3rd/ morning of the 4th of January.

The Quadrantids can be quite an impressive shower with rates (ZHR) of up to 120 meteors per hour at the showers peak (under perfect conditions) and can sometimes produce rates of up to 200 meteors per hour. The peak is quite narrow lasting only a few hours, with activity either side of the peak being quite weak.

Due to a waxing gibbous moon, the best time to look is after midnight and through the early hours when the moon sets in time for us to see the peak which is 07:20 UT.

The radiant of the Quadrantids (where the meteors radiate from) is in the constellation of Boötes, however many people are mislead in thinking they need to look at the radiant to see the meteors – this is not true. Meteors will come from the radiant, but will appear anywhere in the whole sky at random. You can trace the shooting stars path back to the radiant to confirm if it is a meteor from the meteor shower.

For more information on how to observe and enjoy the Quadrantid meteor shower, visit meteorwatch.org

Planets

Mercury is low down in the southeast before sunrise in the first week of January.

Venus will be shining brightly in the southwest until May and will pass within 1° of Neptune the furthest planet on the 12th and 13th of January. You can see this through binoculars or a small telescope. On the 26th Venus and the Moon can be seen together after sunset.

Venus

On the 5th of January, Earth will be at “Perihelion” its closest point to the Sun.

Mars brightens slightly to -0.5 during January and can be found in the tail of Leo; it can be easily spotted with the naked eye. The red Planet is close to the Moon on the night of the 13th/ 14th January.

Mars

On January 2nd Jupiter and the Moon will be very close to each other with a separation of only 5° with Jupiter just below the Moon. Jupiter will continue to be one of the brightest objects in the sky this month.
Jupiter

Saturn now lies in the constellation of Virgo and follows after just after Mars in Leo.
Saturn

Uranus is just barely visible to the naked eye in the constellation of Pisces and can be easily spotted in binoculars or small telescopes throughout the month. The Moon will pass very close to Uranus on the 27th and will be just 5.5° to the left of the planet.
Uranus

Moon phases

  • First Quarter – 1st and 31st January
  • Full Moon – 9th January
  • Last Quarter – 16th January
  • New Moon – 23rd January

Constellations

Credit: Adrian West

In January the most dominant and one of the best known constellations proudly sits in the south of the sky – Orion the hunter.

Easily distinguishable as a torso of a man with a belt of three stars, a sword, club and shield, Orion acts as the centre piece of the surrounding winter constellations. Orion is viewed upside down in the Northern sky as seen from the Southern hemisphere.

Orion contains some exciting objects and its most famous are the Great Nebula in Orion(M42), which makes up the sword and is easily seen in binoculars or a telescope and bright Betelgeuse, Orion’s bright alpha star (α Orionis). Betelgeuse is a red supergiant many times larger than our Sun; it would engulf everything in our solar system out to the orbit of Jupiter, if the two stars swapped places. Betelgeuse will eventually end its life in a Supernova explosion and some people believe that it may have already exploded and the light hasn’t reached us yet. It would make for a fantastic sight!

The Great Orion Nebula by Patrick Cullis
The Great Orion Nebula. Image Credit: Patrick Cullis

If you draw an imaginary line through the three belt stars of Orion and keep going up and to the right, you will come to a bright orange coloured star – Aldebaran (α Tauri) in the constellation of Taurus.
Pleiades Cluster/ Seven Sisters

Taurus depicts a head of a bull with Aldebaran as its eye with a V shape that creates long horns starting from what we call the Hyades cluster, a V shaped open cluster of stars. If you continue to draw a line through the belt stars of Orion, through Aldebaran and keep going, you will eventually get to one of the gems in Taurus – The Pleiades cluster or Seven Sisters (M45) a stunning cluster of blue and extremely luminous stars and from our vantage point on Earth, the most recognisable cluster with the naked eye. A great object to scan with binoculars. A great object to hunt for with a small telescope is the Crab Nebula (M1) near the end of the lower horn of Taurus.
The Crab Nebula
The Crab Nebula

If you go back to our imaginary line drawn through the belt stars of Orion and draw it in the other direction, to left and below, you will come to the very bright star Sirius (α CMa) – The Dog Star in Canis Major. Sirius is the brightest star in the sky and is only 8.6 light years away, it is the closest star visible to the naked eye after the Sun.

Sirius along with Betelgeuse and Procyon (α CMi) in Canis Minor, form an asterism known as the Winter Triangle.

Directly above Orion and the Winter Triangle are the constellations of Gemini (The Twins), with the two bright stars of Castor and Pollux marking their heads and Auriga the charioteer, with its bright alpha star Capella (α Aur). Auriga is host to M36, M37 and M38 which are globular clusters and easily seen through binoculars or small telescope and Gemini plays host to M35.

M37

Only a few of the objects available to see have been mentioned, so get yourself a good map, Planisphere or star atlas and see what other objects you can track down!

Posted on by Tammy Plotner

Observing Alert: Bright Spot On Uranus Reported

The bright spot on Uranus observed with Gemini

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There’s nothing like a dynamic solar system… and right now another planet is being heard from. According to various sources, a bright spot – possibly a developing storm – has been spotted on Uranus.

“Professional observers this morning (October 27) reported a very bright cloud on Uranus, using the Gemini telescope, and need amateur confirmation if possible, to obtain a rotation period.” says John H. Rogers, Jupiter Section Director, British Astronomical Association. “Near-infrared filters may have the best chance of detecting it. It was recorded in the 1.6 micron band, which is further into the IR than amateurs can reach, but your usual near-IR filters might be successful. I think that methane filters are not especially promising, as these clouds on Uranus are overlaid by a methane-rich layer of atmosphere, but would be worth trying anyway. Anyone who has a 1-micron filter should have a go too.”

At this point in time, information is limited, but professional images taken using the 8.1-metre Gemini Telescope North on Hawaii have recorded a region said to be ten times brighter than the planetary background. The bright spot is believed to be attributed to methane ice. ““This is an H-band image, centered at 1.6 microns, close to the wavelength of maximum contrast for such features. Its contrast will decrease with decreasing wavelength, and will likely not be detectable by amateur astronomers, except possibly at the longer CCD wavelengths where the Rayleigh scattering background can be suppressed.” says Larry Sromovsky, of the University of Wisconsin-Madison. “Looking with a methane band filters at 890 nm might be productive, especially if the feature continues to brighten.”

“The feature is not very large; instead its prominence is due to its high altitude, placing it above the intense absorption of methane in the deeper atmosphere. This is much higher than the 1.2-bar methane condensation level and thus it is expected to be predominantly composed of methane ice particles.”

Dr Sromovsky added: “The latitude of the feature is approximately 22.5° north planetocentric, which is a latitude nearly at rest with respect to the interior. So it should rotate around Uranus’ axis with nearly a 17.24-hour period. At the time of the image, the feature’s longitude was 351° West. That could change slowly in either direction.

“The low latitude is unusual. Previous exceptionally bright cloud features on Uranus were at close to 30° North, both in 1998 (Sromovsky et al. 2000, Icarus 146, 307-311) and in 2005 (Sromovsky et al. 2007, Icarus 192, 558-575). The 2005 feature oscillated ±1° about its mean latitude. The new feature might also oscillate in latitude, in which case its longitudinal drift rate might also vary with time.”

Hang in there, UT readers! Right now we have two of our best astrophotographers doing their best to give us an exclusive look! This page will be updated as more information becomes available.

Partial Quote Source: Skymania News Release.